一种无证书签名方案的分析与改进  

Analysis and Improvement of a Certificateless Signature Scheme

作　　者：史华婷 万中美[1] 

机构地区：[1]河海大学理学院,江苏南京211100

出　　处：《计算机技术与发展》2017年第5期133-137,143,共6页Computer Technology and Development

基　　金：国家自然科学基金资助项目(61103183)

摘　　要：无证书公钥密码体制虽然解决了基于身份密码体制中的密钥托管问题,但是当随机预言模型被具体的哈希函数实例化时,将会导致无证书签名方案在现实生活中的不安全。标准模型下的证明为无证书签名方案提供充分的保障。通过两种具体的攻击方法,对李艳琼提出的标准模型下的无证书签名方案进行安全性分析,指出其不能抵抗公钥替换攻击和恶意的KGC攻击。针对存在的安全问题,对原来的无证书签名方案进行改进,并加强方案与公钥、私钥等参数的联系,从而达到安全要求。在标准模型下,基于NGBDH问题和Many-DH问题的困难性假设,改进的无证书签名方案在自适应选择消息攻击下是存在性不可伪造的。与李艳琼提出的方案相比,改进后的无证书签名方案在安全性上有了更高的优势。Although certificateless cryptography solves the key escrow problem in the identity-based public cryptography, a CLS scheme may not be secure in the real world when the random oracles are instantiated by concrete hash functions. The security of certificateless sig- nature scheme can be proved adequately in the standard model. Security analysis has been carded out for Li Yanqiong＇ s CLS scheme by detailed method attack, whose results show that the scheme is not secure against key replacement attacks and malicious KGC attack. In view of the existing secure problems, an improved certificateless signature scheme has been proposed, which enhances the contact with the public key, private key and other parameters, to achieve the safety requirements. Based on the NGBDH problem and Many-DH problem in the standard model, an improved CLS scheme is proved secure against existentially under adaptive chosen message attack. Compared with Li Yanqiong＇ s scheme, the improved CLS scheme has higher advantages in the security.

关 键 词：无证书签名 标准模型 NGBDH问题 Many-DH问题 

分 类 号：TP309[自动化与计算机技术—计算机系统结构]